The invention relates to a memory module system, an adapter card, an adapter card with a data buffer device, and in one embodiment an advanced memory buffer (AMB), and to a method for operating a memory module system.
Conventional computers, e.g., PCs (personal computers), laptops, notebooks, workstation computers, server computers, etc., generally include a main printed circuit board, the motherboard, on which one or a plurality of CPUs (central processor units) may be provided, as well as one or a plurality of memory controllers, an appropriate BIOS component, and one or a plurality of plug contacts for memory modules, etc.
The different components of the motherboard, e.g., the above-mentioned memory modules, the CPU, the memory controller, etc. may—for the exchange of corresponding data, address, and/or control signals—be connected with each other via one or a plurality of bus systems.
As memory cards—to be plugged into the above-mentioned plug contacts—appropriate unbuffered DIMM memory modules may, for instance, be used (DIMM=Dual In-Line Memory Module) which each include a plurality of memory devices, e.g., a plurality of RAM memory devices, in one embodiment DRAMs (DRAM=Dynamic Random Access Memory).
In a plurality of applications—in one embodiment e.g., with server or workstation computers, etc.—memory modules with upstream data buffer elements (buffers), e.g., “R-DIMMs”(R-DIMM=registered DIMM), “FB-DIMMs” (FB-DIMM=Fully Buffered DIMM), etc. may also be used instead of the above-mentioned unbuffered memory modules.
In the case of conventional memory module systems with buffered memory modules, a plurality of FB-DIMMs may, for instance, be inserted into corresponding memory plug contacts of a motherboard and thus be connected in series in the form of a corresponding “daisy chain”.
In the case of R-DIMMs, the address and control signals—which are, for instance, output by the memory controller or by the CPU—may be (shortly) buffered by appropriate buffer devices (“registers”) of the respective R-DIMM, and correspondingly similar address and control signals may—in a time-coordinated, possibly multiplexed or demultiplexed manner or in a converted form, respectively—be transmitted to the memory devices, e.g., DRAMs, of the corresponding registered DIMM.
Contrary to this, the (reference) data signals—output by the memory controller or the CPU, respectively—may directly, i.e. without buffering by a corresponding buffer device, be transmitted to the memory devices (and—vice versa—also the (reference) data signals output by the memory devices directly—without the interconnection of a corresponding buffer device—to the memory controller or the respective processor, respectively).
Contrary to this, in the case of FB-DIMM memory modules, both the address and control signals exchanged between the memory controller or the respective CPU, respectively, and the memory devices, and the corresponding (reference) data signals are buffered by corresponding data buffer devices, in one embodiment AMBs (advanced memory buffers) of the respective FB-DIMM and only then transmitted to the memory devices or the memory controller or the CPU.
In conventional motherboards that are designed for FB-DIMMs, only FB-DIMMs, not, however, the above-mentioned R-DIMMs, unbuffered DIMMs, etc. can, for instance, be used.
FB-DIMMs are substantially more expensive than registered DIMMs and unbuffered DIMMs.
For these and other reasons, there is a need for the present invention.